The present invention relates generally to the field of synthetic filament production. More specifically, the present invention relates to the field of liquid finish applicators and methods whereby a liquid finish is applied onto surfaces of synthetic filaments.
Synthetic filaments are traditionally produced by various spinning techniques. For example, synthetic filaments may be melt-spun by extruding a melt-spinnable polymer through relatively small-sized orifices in a spin pack to form a stream of filaments that is substantially immediately solidified in a quench cabinet. The filaments are thereafter continuously taken up by a high speed winder to form a generally cylindrical package. Depending on the intended end use, the filaments may be undrawn or may be subjected to a drawing step prior to being taken up to form the package.
The solidified filaments are typically passed through a metered finish applicator, which applies a liquid finish material (colloquially referred to as a xe2x80x9cfinish oilxe2x80x9d) so as to lubricate the filaments to reduce filamentary friction and/or to achieve desired processability characteristics. Typically, a finish applicator mounting unit supports a plurality of fixed-position finish applicator nozzles that each include a slot to receive the individual filament threadlines. A portion of the slot against which the filaments are guided includes a small opening for the finish oil. Thus, as the filaments pass through the finish applicator nozzle during production, the finish oil is supplied to the slot and thereby coated onto the filaments.
The finish applicator nozzles are typically formed of a durable, low friction material, such as a ceramic material. Over time, however, the small amount of friction between the filaments moving at a relatively high speed and the stationary finish applicator nozzle causes some wear to be experienced in the latter. A greater amount of friction on the moving filaments will result as the finish applicator nozzle experiences greater wear which, in turn, is detrimental to the filaments. Too great a frictional force against the filaments can, in extreme cases, cause filament breakage requiring production down time.
Recently, U.S. Pat. No. 5,679,158 (the entire content of which is expressly incorporated hereinto by reference) suggested providing a finish applicator assembly with applicator nozzles removably received in a corresponding aperture of a mounting unit. While the applicator nozzles of this U.S. ""158 patent are more easily accessible for the purpose of cleaning, repair and/or replacement, some improvements are still desired.
For example, it would especially be desirable for finish applicators and methods to be provided which would increase the wearability of the finish applicator thereby lessening the friction experienced between the applicator and the moving filaments over a significantly greater period of time than can now be accomplished. It is towards fulfilling such a need that the present invention is directed.
Broadly, the present invention is embodied in apparatus and methods whereby a finish oil may be applied onto a moving filament by a stationary, yet periodically movable finish applicator. The finish applicator is most preferably annular and is thus capable of being rotated relative to the traveling filament so as to sequentially bring at least one and another arcuate applicator surface segments into contact with the travelling filament. By continually exposing different surface segments of the finish applicator to filament contact at different times, the amount of wear experienced by a single one of the surface portions is minimized. As such, the finish applicator is capable of being kept in production for prolonged time periods and thus minimizes (if not eliminates entirely) at least some of the problems noted previously with respect to conventional finish applicators.
Thus, in one especially preferred aspect of the present invention, liquid finish is applied to a travelling filament by bringing the travelling filament into contact with an arcuate surface portion associated with a normally stationary, but rotatable, annular finish applicator, and thereafter periodically rotating the annular finish applicator to bring at least one other arcuate surface portion thereof into contact with the travelling filament. Most preferably, an actuator assembly is provided having first and second actuator fingers which are capable of relative separable rectilinear movements towards and away from one another. These actuator fingers, in an especially preferred embodiment, are each pivotally moveable and magnetically coupled to one another. As such, separable movement will in turn cause that one of the actuator fingers connected to the annular finish applicator to pivot thereby rotating the later to expose a xe2x80x9cfreshxe2x80x9d arcuate surface region in contact with the filament.
These and other aspects and advantages will become more apparent after careful consideration is given to the following detailed description of the preferred exemplary embodiments thereof.